Production systematics

Production systematics of cosmogenic nuclides are studied by different approaches  

In all such studies, multi-nuclide analyses are the rule, and the various approaches are often also combined. Note that a commonly used simplification is to assume that meteoroids had spherical shapes. 

Here Texp is the exposure age, X is the decay constant of the radionuclide, and A, 

Production rates P in [10 cc STP/(g x Myr)] for He, Ne and Ar, and in [lO cc STP/(g x Myr)] for Kr and Xe (1 cc STP=2.687 X atoms). All values from Eugster (1988), except P( Ar) for which a 12% lower value than that given by Eugster (1988) is adopted (Schultz et al. 1991 Graf and Marti 1995). e/ Ne is the ratio of the cosmogenic component. The shielding correction proposed here is approximately valid only for Ne/ Ne 1.08-1.10, and may fail completely for the rare very large meteorites (see text). 

P( Ar) values, although the issue is not settled (Eugster et al. 1998b). 

---

Masarik, I, Reedy, R. C. (1995) Terrestrial cosmogenic-nuclide production systematics calculated from numerical simulations. Geochim. Cosmochim. Acta, 136, 381-95. 

Later on, Kazanskii and his co-workers, using Raman spectroscopy to analyze the reaction products, systematically studied the contact reactions of cyclic hydrocarbons, especially cyclobutanes and cyclopentanes. The important results that they obtained, none of which was invalidated when more sophisticated analytical tools were available, may be summarized as follows ... 

In the following, we will first discuss the production systematics of cosmogenic nuclides in meteorites. Next, we will present the distributions of cosmic ray exposure ages of different meteorite classes and discuss what they tell us about meteorite transport from the various parent bodies to Earth. We will also consider so-called complex or pre-exposure histories, which is when a meteorite also contains cosmogenic nuclides acquired before it became the body with the size and shape it had immediately before it fell to Earth. Some of these meteorites represent material that once was within the top... 

In meteorites, short-term cosmic ray flux variations can be recognized by measuring the activity of a radionuclide with a short half-life in meteorites with a known fall date. Longer-term variations are studied by comparing apparent production rates of stable (noble gas) nuclides based on various pairs of a stable and a radioactive nuclide, or by comparing experimental and model data (see Production systematics subsection). 

Masarik J, Kollar D, Vanya S (2000) Nnmerical simnlation of in situ production of cosmogenic nnchdes Effects of irradiation geometry. Nncl Instr Meth Phys Res B 172 786-789 Masarik J, Reedy RC (1995) Terrestrial cosmogenic-nnchde production systematics calcnlated from nnmerical simnlations. Ea Planet Sci Lett 136 381-395 Masarik J, Reedy RC (1996) Monte Carlo simnlation of in situ produced cosmogenic nnchdes. Radiocarbon 38 163-164... 

Either NbgOg or TagOs is heated with an alkali hydroxide or alkali carbonate. Salts of differing composition are obtained, depending on the reactant ratios, the temperature, and workup of the reaction product. Systematic investigation has shown that the system alkali oxide-pentoxide contains a wide range of compounds. 

Service development Are service products systematically developed within a defined development process ... 

In order to specify the secondary or tertiary nature of these other non-primary products, complementary experiments can be carried out which study the reactions of the primary products systematically, either alone or in the presence of the reactants or of other primary products. The principle of least change of structure could also be used, which states that the structural changes which enable a species to change into another must be as small as possible. 

This discovery led us to study free radical production systematically in extruded wheat flour to determine whether free radical production was related to extrusion conditions and chemical changes in wheat proteins, and to distinguish the relative contributions of heat, shear, and oxidizit lipids in formation of protein radicals. 

Medic-Saric, M., Rastija, V., Bojic, M., and Males, Z. 2009. From functional food to medicinal product systematic approach in analysis of polyphenolics from propolis and wine. NutrJ8 33. 

To identify all the possible products systematically, a multiplication table of symmetry operations can be drawn up in which each row and column of the table has one of the symmetry operations as a heading the body of the table then contains the operation resulting from the product of that row and column. The starting point for the case of HjO is given in Table 2.1 and it is left to the reader to complete this following the instructions in Problem 2.1. 

---